|
|
Heat Pumps
A heat pump is an appliance that extracts heat from one environment and discharges it into another. Most heat pumps are powered by an electric motor, but can be powered by a fuel burning motor, as some camper refrigerators are. In heating mode, a heat pump will collect heat from the outdoor unit (condenser), and discharge it inside through the air handler. With the help of a reversing valve, the flow of refrigerant moves in the opposite direction and heat is extracted from the air handler and discharged outside, creating air conditioning.
In some tropical areas, domestic hot water is generated in air conditioning mode by cooling the condenser with water; the heated water is stored until needed.
Its basic components are: the air handler; comprised of a cabinet, blower, evaporator coil, and controls, the condenser or outdoor unit, and piping to create a closed loop of refrigerant between the two.
In some areas the heating demand can be two or three times the cooling demand. Because a heat pump’s efficiency drops as the outside temperature goes down, electric heating elements will be installed as a backup to assist the heat pump when needed.
Accessories include: an air filter, electronic air cleaner, or high performance media filter, and a humidifier. A condensate pump might be used to remove the water produced be the dehumidifying action of the air conditioning.
A zone control panel and motor actuated dampers will be attached to the unit or in the ductwork if the system is zoned.
Routine maintenance includes replacing the air filter or cleaning the electronic grids, and cleaning the humidifier. Heat pump humidifiers can be of the steam generating type, which will be line voltage powered, so caution must be taken to shut off the power supply before servicing.
Hydro-Air
When a residence is too large for a single warm air furnace, a hydro air system is often used instead of multiple furnaces. A Hydro Air system uses air handlers with hot water coils and can be located a distance from the fuel burning source of heat.
Hydro-air systems use a fuel burning boiler or hot water heater to produce hot water. The hot water is piped to an air handler, sometimes called a fan coil. Inside the air handler is a multi-row coil, through which the hot water is circulated. Air is then passed over the coil and ducted to the space. An aqua stat or time delay can be used to allow the coil to heat up before turning the blower on, preventing the discharge of cool air that can feel uncomfortable in heating mode.
Accessories can include: an air filter, electronic air cleaner, high performance media filter, humidifier, and an evaporator coil for central air conditioning. A system with air conditioning might have a condensate pump to remove the water produced by the dehumidifying action of the coil.
If the system is zoned, a zone control panel and motor actuated dampers will be installed on or inside the air handler and ductwork.
Routine maintenance of the air handler includes replacing the air filter or cleaning the electronic air cleaner grids, and cleaning the humidifier.
If an oil burner is making the hot water, annual servicing by a professional is recommended, since special instruments are needed to set the burner up to the proper fuel-to-air mixture ratio.
If city or propane gas is making the hot water, nothing needs to be serviced on a regular basis, unless soot is evident or low water temperature develops.
Some hydro-air systems use a boiler that has anti-freeze in it. This should be tested for freeze protection and replaced according to manufacturers specifications, usually every three or four years.
Air To Air Exchangers
Routine maintenance involves replacing or cleaning the filters if so equipped, and keeping the outside air intake free of debris. After years of service the exchanger will become crusted with grease and dirt that collects during condensation. Removing this accumulation will probably take solvents or degreasers and require opening up the cabinet and compartments.
Electric Furnaces
Routine maintenance includes monthly replacing the air filter or washing the electronic air cleaner grids during constant use, and cleaning the humidifier. Humidifiers can be of the steam generating type, which will be line voltage powered, and should be shut off before servicing. Deadly high voltage conditions exist inside the cabinet; leave control servicing to a qualified technician.
Electronic Air Cleaners
Electronic air cleaners will usually operate at 95% efficiency, allowing little or no dust to pass through. The dirtier they get, the lower the effectiveness, so clean grids are a must. Before removing the screens and grids for cleaning, it is imperative to shut the power off and wait a few seconds to allow the grids to lose the static charge. They are dishwasher safe as long as they fit inside. If not, sloshing around in a tub of hot soapy water will loosen dirt that can be blasted off with a garden hose.
Extreme caution must be taken when handling to protect the grids and the person handling them. The plates are very sharp, and can cut like razor blades. The fine wires stretched across the grids are delicate and crucial to proper function. Proper spacing between the grids is important. Do not bend or distort them.
If the grids are not completely dry when installing them, do not turn the power back on; damage to the power pack can occur as the water will short the grids out. If in doubt about the dryness, leave the power switch off for a day or two; the air flow will take care of any residual water. Arrows one the grids will display the correct direction for air flow. Improper installation will render them useless. If the air cleaner was installed correctly in the return air duct by the original HVAC mechanic, air flow will be going from the duct toward the appliance. The arrows should do the same.
Gas Furnaces
Routine maintenance includes: monthly filter replacement or washing the electronic air cleaner grids when in constant use, and cleaning the humidifier if so equipped. A properly functioning gas burner will not need cleaning. Black soot is evidence of an incorrect air mixture or other malfunction, and should be checked by a qualified serviceman.
Humidifiers
Furnace mounted units can be by-pass, steam, mist, wick, and powered. Some mount in the ductwork while others are attached to the plenums on the furnace. Whatever the model, mineral deposits from the water will reduce the effectiveness of the humidifier. Be sure to turn the water and humidistat off before servicing.
Special chemicals can be used to clean mineral deposits, but one of the safest is vinegar. A 50% mixture of vinegar and water will usually dissolve or help clean away deposits. If the humidifier has a drum with a belt, replacement of the belt at the beginning of the heating season can be the easiest fix if the water has a high mineral content. If the humidifier has screens or is the wick type, some corrosion can occur as well as build up.
Heat pumps and electric furnaces usually have steam humidifiers to increase output. They are line voltage powered and must be unplugged or disconnected before servicing to avoid injury. With the exception of some mist type humidifiers, all have a reservoir. Stagnant water sitting in the reservoir during the off season can be a breeding ground for bacteria. Turn the water off and clean the humidifier if possible when heating season has ended.
Other than mineral deposits, the most common problem is sediment in the water supply. The float inlet valve has a tiny hole that easily clogs. The float is usually made of plastic, and if cracked will fill with water and sink. The valve will be stuck open and the reservoir will overflow. Use caution when scraping deposits off the float. If the deposits cannot be removed, replace the float or it will sink and cause an overflow.
Oil Furnaces
Routine maintenance includes; monthly filter replacement or washing the electronic air cleaner grids when in constant use, cleaning the humidifier if so equipped, and an annual tune up of the burner.
An oil burner tune up includes a nozzle and filter replacement, heat exchanger and smoke pipe cleaning, and a fuel to air mixture adjustment. Since the mixture adjustment requires the use of special instruments to meet federal standards, it is best left to a professional to obtain peak efficiency.
Room Air Conditioner
Not obvious is the fact that they need maintenance routinely, just like any other machine. The filter, usually located behind the front grill, needs to be washed. The condenser coil at the back of the unit can accumulate a lot of debris, and might require a special chemical bath. All air conditioning systems, large or small, need good air flow across the evaporator coil and the condenser coil. Efficiency and performance drop rapidly as air flow decreases. Lose enough air flow and the unit will burn out. Rodents can nest inside when not in use, and can foul up the unit in many ways. Wasps and hornets, as well as the honey bee find finned coils to be comfortable nesting places. Nests and dead insects can ruin the air conditioner.
Wood Furnaces
Aside from ash removal, routine maintenance include air filter replacement or washing the electronic air cleaner grids, cleaning the humidifier, and an annual tune up of the oil burner if so equipped. Special instruments are needed to set the correct air to fuel
Motorized Dampers
Zone control of a forced air system is done with a thermostat for each zone. The thermostat signals a control panel, which in turn opens the corresponding zone damper and turns on the appliance (furnace, air handler etc.). Some older zoned systems do not use a control panel. The thermostat controls the damper, and the damper has trip switches that turn the appliance on (similar to zone valves in a hydronic system).
The control panel is necessary for modern systems to control the change-over from heating to cooling and vice-versa. The control panel also allows for selection of normally open or normally closed positions of the dampers for purging after the thermostats are satisfied. Dampers come in a variety of designs. Opposed blade dampers use a motor to open and close them. This damper design has the appearance of accordion or folding panels when closed, and metal slots when open.
Single blade dampers can use a motor to open and close them, or use a spring to close them and a motor to open. This type will remain in the closed position at rest. A single blade with spring open uses the motor to close, and is open at rest.
Portable Air Conditioners
An air conditioner cannot create cooling; it can only relocate the heat. This heat is removed in two ways, as an actual temperature drop, and as water. The refrigerant carries the heat outdoors where it is discharged: while the water, called condensate, is collected separately and pumped or drained away. When installed properly, most air conditioners perform these operations automatically. The exception to this is the portable air conditioner, which must be vented and drained by the user; but it is these features which give the portable air conditioner its flexibility.
There are two types of portable air conditioners. The first or "evaporative" cooler uses water to relocate the heat. This type of portable air conditioner is primarily effective in dry climates, as humidity is a byproduct of the cooling cycle. This type of portable can often be found in 12 volt models that adapt well for use in cars, campers, boats, etc. The second type of portable air conditioner uses a refrigerant and is very much like the standard window unit, except that it usually comes on wheels and is meant to operate on the room's floor. They plug into a standard 120 volt outlet, and a "vent" must be installed through a nearby window. A condensate pan must also be dumped periodically, when in use; although some models also exhaust the condensate through the window vent.
Developed mostly for commercial use, the portable air conditioner was designed to supply extra cooling to temperature sensitive areas during extreme weather conditions. They are quite useful in protecting equipment and inhabitants from over heating when the temperature demands overcome the building's permanent HVAC system. Residential versions are now available, and can be used in many applications where cooling is desired.
As mentioned earlier, with little installation effort, they can be used in the garage, barn, camper, enclosed porch, etc. You can watch TV with it in the den, then take it to bed with you at night. Even though they are portable, cooling is a slow process, and when the unit is relocated, it will take time to condition the air.
Problem Areas
It's about the room over the garage that just won't co-operate. You rechecked the heat loss, gave it a little extra, took extra care insulating the trunk line, but the room is still cold. The cooling worked okay last summer, but it just won't heat right. How come? Location, location, location!
It isn't a situation of heat loss, but of heat gain. The other second floor rooms are gaining heat from the room below. The air temperature of the first floor ceilings can easily reach into the eighties, and the air going up the stairways can also be this warm. Both sources of heat reduce the demand of the second floor. Except, of course, that room located over the garage. The room over the garage is losing heat from below instead of gaining. It is an island in the cold with one small bridge, the doorway, connecting it to the main house. Extra outlets won't help. They only function when the system is running, when the thermostat calls.
That playroom in the basement has the opposite problem. It heats fine, but when the cooling comes on, it’s freezing down there. Sometimes, it even needs heat when the upstairs rooms are calling for cooling. How come? Again, location. In this case, it's a situation of heat loss all year long. Even in the summer, especially in spring, this room has a heat loss that is usually ignored in calculations.
Both rooms, the room over the garage and the room in the basement, are victims of reverse heat loading. Reverse heat loads are gains or loads that were assigned heat transfer values of zero during calculations instead of being assigned a negative factor.
When the heat gain of the basement was calculated, the floor was given a heat gain value of nothing, because it does not gain heat. That is correct, but inaccurate. The floor in fact loses heat, even during the cooling season.
The best solution in both cases is to isolate these areas by zoning. A special control panel can alternately supply heat to the basement from the same system that provides cooling to the floor above it.
Solar Cooling
The words "solar" and "cooling" might be an oxymoron, but the sun can be a source of cooling in a number of ways. The simplest evaporative air conditioning system, a pond of water on a flat roof, uses the sun to help evaporate the water. Evaporation of the water cools the roof and the space below.
Any solar heating system, active or passive, can become a cooling system. Shading the collector during the daytime and exposing it to cool night time temperatures allows it to lose energy. As the outdoor temperature rises during the day, the cooler storage medium will absorb the heat in the home. At night the cycle is repeated, and the stored heat is given up to the cool night air.
Designing a passive system for cooling requires some form of daytime shading. A retractable awning or an overhang extension of the roof to shade the glazing from the high summer sun but expose the glazing to the low winter sun will suffice. Moveable insulated panels work better but add to the expense and mechanical complexity. Doors or glazing panels that open will allow the cool night air in to remove stored heat.
Active systems can benefit from shading, but work almost as well without it. Operating the collection system at night reverses the energy transfer. Heat is removed from the storage facility and radiated out the collector. The storage facility can collect the heat of the home during the daytime and expel it at night. Areas that do not experience dramatic temperature swings from day to night, or that have warm nights need a heat pump solar system to capitalize on the reverse flow. Areas that experience extreme temperature swings, such as the desert, can construct heat pump systems efficient enough to produce refrigeration.
Solar cells that produce electricity put a new perspective on cooling. The electricity generated can power conventional air conditioning equipment day or night. If sufficient power is not available from the storage batteries, current from the local utilities can run the system.
Window Air Conditioners
Window units, or the larger version known as through-the-wall units, are the smallest of the self contained machines. Inside of the cabinet is a compressor, condensing coil, evaporator coil, blower, controls, and maybe a little ductwork. The ductwork and possibly a damper will allow the unit to draw fresh air in or re-circulate 100% of room air. The high end units can have electronics with timers, accurate temperature sensors, and remote control. By using sound absorbing materials and quieter motors, manufacturers have improved these machines over the years. The efficiency ratings are not as high as central systems (EER ratings) and versatility is limited because all of the cooling is blown into one room, but they get the job done when needed.
Not obvious is the fact that they need maintenance routinely, just like any other machine. The filter, usually located behind the front grill, needs to be washed. The condenser coil at the back of the unit can accumulate a lot of debris, and might require a special chemical bath. All air conditioning systems, large or small, need good air flow across the evaporator coil and the condenser coil. Efficiency and performance drop rapidly as air flow decreases. Lose enough air flow and the unit will burn out. Rodents can nest inside when not in use, and can foul up the unit in many ways. Wasps and hornets, as well as the honey bee find finned coils to be comfortable nesting places. Nests and dead insects can ruin the air conditioner.
Wine Cellars
Areas of the world that have sub-soil temperatures of 55° F or less open the opportunity to construct a wine cellar that does not require supplemental cooling. A room temperature between 50° F and 60° F with a relative humidity of 60% to70% will keep the cork swollen and air from entering and spoiling the contents of the bottle. Any concrete bunker, root cellar, or bomb shelter can offer the dank, dark, cool conditions ideal for the preservation of fine wines.
If subterranean temperatures are too high or the room is to be built inside of an existing basement, a vapor tight, insulated room is the best action. Standard stud wall construction is acceptable, but the better the insulation the less energy will be consumed by the cooling device. The use of high-R sheathing to line the inside will not only improve the insulation but help to form a vapor barrier. It is best to line the entire interior with polyethylene to prevent moisture loss. Exterior grade plywood can be used for paneling since the shelving or racks should pretty much cover the walls. Real wood paneling can be used as well. Gypsum board will have a tendency to mildew unless sealed with a mildew resistant paint. Racks are constructed in such a way as to keep the bottles in a "reclining" position so corks are wet and oxygen stays out.
One unique method of cooling the wine cellar is to run a loop of copper hot water baseboard tubing around the room and pipe the domestic water through it. Well water and city water that runs deep in cool soil will absorb heat from the room as it passes through the loop. There are two major drawbacks to this method. In summertime the water might be warmer than desired at the tap, and the loop of piping in the wine cellar will have a tendency to drip as water vapor condenses on it. The most dependable way is to use a refrigeration unit. A window or through-the-wall air conditioner can handle the cooling, but will dehumidify as well, and that is bad. Special equipment is available that will turn the room into a medium temperature walk-in cooler. These machines are designed to cool without drying the air. Different outputs allow the unit to meet the demands of the size of the room.
Zoning
If a house has one thermostat that controls the heating and cooling for the entire structure, it has one zone. If the house has more than one thermostat, each thermostat is controlling a selected area or zone. Zoning offers more control over the comfort of the entire space.
The benefits of zoning depend on the size of the house, the style of construction, and the type of system. A 1000 square foot ranch may not be cost effective to zone for forced air heat, but would be efficiently zoned room by room with electric heat. A cape with a small second floor would be difficult to zone with a forced air system, but easy with hot water baseboard.
There are two common ways to control the comfort of a home. One way is to install separate systems for each area, allowing each area to be independent of the other for heating and cooling demands. Another method is to use one piece of equipment and create zones. A forced air system uses a control panel and motorized dampers working in separate trunk lines to make comfort zones. A hot water system uses zone valves or circulators feeding individual loops to form individual comfort zones. Zoning is ordinarily use to separate sleeping quarters from living areas, or first and second floors. Multi-level structures have different demands on each level, and zoning increases the comfort control. In a central system using one unit for heating and cooling, the full output of the machine can be directed to each zone to deliver maximum capacity when needed. This means that a house cooled with one four-ton system can have all four tons delivered to each zone. The same house cooled with two 2-ton systems can only deliver 2 tons of cooling to each zone.
|
|
|
Air Conditioning Problem Troubleshooting Page
This page contains some Air Conditioning problems and parts that in use to repair the problems. These problems occur most often every summer. You can repair your air conditioner and save money!
Listed below are many of the air conditioning problems that happen on a daily basis. I wanted to list some of the problems and give you a chance to purchase the parts, and repair your air conditioner yourself.
Please always, make sure all electrical power is turned off before attempting to do any heating or air conditioning repairs.
Problem #1: Outdoor condensing fan motor has stopped running
This problem could be caused by a bad motor run capacitor. If your motor capacitor is not the problem, then more than likely you need a new motor. Is the fan blade tight, stiff or hard to turn? If the fan blade is hard to turn then you probably need a new motor.
Problem #2: Air conditioner compressor will not start
When power is applied to the air conditioning outdoor unit the fan starts, but you hear a sound like the compressor is trying to start, "UGGG"..., for about 5 to 10 seconds and then all you hear is the outdoor condenser fan run. The compressor is locked and will not start. What is happening is the compressor is trying to start, but because the compressor motor is locked it tries to start for a few seconds and then because of the high amperage being drawn goes off on internal overload. The internal overload protects the compressor windings from overheating and burning up. Some compressors just have a hard time starting after sitting all winter long. Some compressors are locked up so bad that you need a new compressor or new air conditioning system. Many times it’s possible to get the compressor started again without having to buy a new compressor or new air conditioning system by using the device "Super-Boost."
The Super-Boost could save you from having to purchase a new air conditioning compressor or system!
The Supco, Super-Boost has the following features that make it a life saver when it comes to air conditioning repair:
The Supco can save stuck compressor by increasing the compressor's starting torque by 500%.
 
 The Supco, Super-Boost is a solid state relay and hard start capacitor no loose parts or complicated wiring. Just wire it across your run capacitor as shown above.
On dual capacitor systems just connect between the "C" and "Herm" terminals. See picture above.
More Features:
The Super-Boost can be used on all PSC single phase 115 volt thru 288 volt air conditioning units from 4,000 to 120,000 BTU.
It can be used on a wide range of air conditioning compressors from 4,000 BTU window units to 10 ton commercial units.
The Supco Super Boost is used for tight or locked compressors, if you have low voltage, or for quick recycling of the compressor.
Problem #3: The problem is a bad compressor or fan run capacitor
The Air conditioner outdoor unit will not come on. Either the outdoor fan does not run, the compressor does not run, or both the fan and the compressor do not run. You checked and reset your breaker and the outdoor unit still does not come on. You can hear a little humming sound, sometimes an "Uggg" inside the unit when power is applied. The "Uggg" is the compressor trying to start. You might hear the low voltage contactor humming. You should pull the disconnect and disconnect the power to your outdoor air conditioning unit. Make sure your electrical power is off before working on any air conditioning equipment. You take the door or cover off your outdoor unit's control box and find a bad, swollen run capacitor. EPA stopped allowing manufacturers to produce capacitors with cancer causing PCB's. Since they stopped allowing the use of PCB's the capacitors now have a shelf life. Sometimes you need a special meter to test the microfarad (MFD) rating. Most of the time you can tell the capacitor is bad because it is swollen up. See the picture for the comparison between a good and bad dual run capacitor. They call them, "Dual" because the capacitor helps run both the fan and the compressor.
 
Bad round dual capacitor on the left. Bad oval capacitor on the left.
Solution: You need to purchase a new capacitor.
Proper Subcooling Charging Techniques
|
| Contactor Problems:
Problem #4: Air Conditioning outdoor condensing unit or heat pump unit will not shut off
It continues to run no matter what you do. The only way you can get the outdoor unit to shut off is turn off the breaker or pull the outdoor disconnect. Also, sometimes when the contactor fails the outdoor condensing unit will not come on at all. Dirt or insects can get in between the contact points while the contactor is off, and cause the air conditioner not to come on at all. When the contactor is stuck in the "On" position (contacts welded together), Ice will form on the indoor evaporator coil and all the way out to the outdoor unit. There could be up to 2 inches of ice form on the line set and outdoor unit compressor. You will not get hardly any air flow through your duct work when this happens because the evaporator has become a complete block of ice. If this is your problem then your contactor points could be stuck, welded together causing the outdoor unit to run continuously. Many times when ants or insects get between the contactor points the outdoor unit will run (burns the insect out), but because of the uneven wear (arcing) in the contact points the contactor will soon fail. Arcing causes a tremendous heat build up and pitting of the contact points. If you are in an area of the country where insects are prominent in and around air conditionings, then I would suggest you blow your contactor out with compressed air or check and make sure you do not have any insects in between the contactor points at the beginning of each cooling season. You might want to keep a spare contactor on hand.
 If your contactor looks like the single pole contactor, with burnt or pitted contacts then you need a new contactor. On the picture is a single pole contactor out of a Rheem air conditioner.
Solution: You need to solve this problem by purchasing a new contactor.
Contactor's Purpose: The contactor has a 24 volt relay, when this 24 volt relay is energized from the thermostat, a call for cooling, the contacts on the contactor close, making a high voltage (220-240) connection to your compressor and outdoor fan, causing the outdoor unit to come on. There are several types of contactors.
Make sure your electrical power is off before attempting to remove or work on air conditioning equipment. Before changing out a contactor or working on an air conditioner make sure you pull the outdoor disconnect or indoor breaker that controls the air conditioner. Turn the furnace off or thermostat off so no low voltage is going through the low voltage wiring.
Term-Lok Compressor Terminal Repair Kit Model TLC-3-10:
Problem #5: Compressor will not run
First, you turn off the power to the air conditioning system. Second you remove the compressor terminal cover and find that one or two of the compressor terminals have burned completely off. That is why the compressor is not running!
Solution: Remove the old burnt terminal/terminals, and use the "Term-Lok" compressor terminal repair kit to replace the burnt terminals and wires.
The "Term-Lok" compressor terminal repair kit save you from having to purchase new compressors or air conditioning systems. Many contractors will tell their customers, "You need a new compressor or new air conditioning unit." Most of the time this is not true! All you need to do is use the "Term-Lok" kit to repair the compressor terminals and you are back in business for a long time. This new Term-Lok compressor terminal repair kit is not cheap, but it is much better than having to get a new compressor or air conditioning system. This compressor terminal kit costs $40.00. The kit is so expensive because of the brass terminal connectors and the way they have permanently connected the #10 gauge wires. The kit is called "Term-Lok" because it actually locks the wires to each compressor terminal. You use a small Allen key wrench to tighten or lock the solid brass terminals to the compressor terminal stubs. There is an Allen screw that can be placed in either the bottom or top of the brass terminal. This makes the installation easy. If there is ¼” left on the compressor terminal studs, then you can use the terminal lock kit to fix your compressor.
 
Above is a Close-up of the three brass terminals with Allen wrench and screws.
Above is a picture of the entire kit. The wires are 36" long #10 Gauge wire |
|
Problem #6: Nothing works on your heating & air conditioning system. The fan will not blow in the fan "ON" position. The gas burners will not light; the outdoor air conditioning unit will not come on.
Solution: Use a Volt Ohm meter, set the meter to "Volts AC," to check and see if you are getting between 24-28 volts between your "C" and "R" terminals on your low voltage board, or between "R" the red low voltage thermostat wire and ground. You might have to tape the blower door safety switch, to keep the voltage on so you can perform this test. Turn your power back OFF after completing this test using the Volt meter. Check for fuses on the furnace control board to see if the furnace has a low voltage protection fuse. If the furnace has a fuse, pull the fuse out and see if it is blown. If the fuse is blown check all your low voltage wiring to make sure it is not grounding out anywhere. It can be pinched wires that are stuck between furnace doors, animals that have chewed through wires and just weathered low voltage wiring that has lost its insulation due to the hot sun. Any wires that are touching together can cause the low voltage fuse to blow. The fuse protects the expensive furnace control board from getting burned up because of a short to ground. If the fuse is blown then you should go to the local hardware and purchase 5 to 6 new fuses. If you do not find the problem that is causing the fuse to blow right away then you will need more than one fuse for testing. If your fuse is OK or your furnace does not have a fuse, and you are not getting low voltage between the "C" and "R" terminals then you might need a low voltage transformer. Some of the transformers just go bad.
What is a Low Voltage Transformer? The job of a low voltage transformer is to take 110 volts AC on the primary end, and transform or lower the voltage to 24 volts on the secondary end. That is why on the transformer label, below it has "PRI" 120, 208, 240 and SEC 24V 40VA. The transformer can be used with multiple voltages either 120 volts, 208 volts or 240 volts. You would hook up the right color coded wire to use the voltage that you have. The color coded voltage wiring directions are on top of the transformer. For example: The white and black wires would be used for 120 volts for most furnaces. The White and Orange wire would be hooked up if you were using the transformer to replace a bad transformer on an outdoor air conditioner or heat pump that uses 240 volts.
International Refrigeration Products Low Voltage Universal Transformer Model TFM4031
Problem # 7: You might consider purchasing and installing the following device if:
1. You have to reset your air conditioning circuit breaker often.
2. If you have electrical storms where the power is going off and on.
3. If the power goes off and on often in your home. If the power goes of and on often in your home then this can ruin a compressor. When your air conditioner is turned off you should wait at least 3 to 5 minutes before you turn it back on. If you do not wait the 3 to 5 minutes then this causes a tremendous strain on the compressor motor because the motor is trying to start without the pressures being equalized. Give your compressor and air conditioning system time for the pressures to equalize before starting your air conditioner again.
Solution: Purchase a delay on make timer. You can set this timer to the length of time you want to wait for the air conditioner to come back on from .03 of a second to 10 minutes. What this timer does is delay the amount of time you want your air conditioner to come on when low voltage power is applied to the timer. This low voltage timer is simple to install. *Some of the new thermostats have this delay feature built into them. If you have a thermostat that has this delay feature, then you do not need to purchase the Delay on Make Timer. If you want to protect your air conditioning system from short cycling and possible compressor damage, then the Delay on Make timer is for you! Remember to turn off all power when working on air conditioning equipment.
 
|
|
Problem # 8: Air conditioner is freezing up
You see frost or ice on the suction line (black insulated line). Any areas that are not insulated are covered with ice. You are not getting hardly any air flow out of your registers. Your evaporator coil is iced up completely. Most of the time this is caused by AC being low on refrigerant charge. There are other causes such as:
1. Dirty air filter or some air flow restriction.
2. Dirty blower
3. Slow or dragging blower motor (might need a new capacitor).
4. Dirty stopped up Evaporator coil (Need to have HVAC tech clean coil)
5. Long Air conditioning runs times. Setting thermostat below 72 degrees with cool outside conditions.
6. A stuck contactor that keeps the outdoor unit running even when the indoor blower is not running or when the thermostat is calling for cooling. Most of the time a freeze up condition is caused by a low refrigerant charge. Since the air conditioning system is supposed to be a leak free, sealed system this means you have a leak somewhere. I would recommend using the Schrader valve caps to make sure that you don’t have a leak in the Schrader valves. These caps have a rubber seal inside of them and insure a leak proof seal.
 
Schrader Caps Installed on an outdoor AC unit.
Schrader caps in box.
What to Check for If Your Air Conditioning System is not working:
1. Check the circuit breaker to make sure the breaker has not tripped. The breaker would probably be a double pole 30, 40 or 50 amp breaker. Even though the breaker looks like it is on I would still flip it all the way to off and back on again just to make sure. Sometimes one leg of a double pole breaker will hold in the other leg and make the breaker appear to look like it is, "ON" when it has actually been tripped.
2. Make sure your thermostat is turned down to a temperature that will allow the air conditioning system to come on. If your thermostat has the little levers on it then it would not hurt to flip the little lever from "OFF" to "COOL”. Sometimes the contacts in the thermostat do not make the connection and flipping the levers will reestablish the connection. I would turn your fan to the "ON" position. Did the fan come on? If the fan did not come on check the switch on the side of your furnace to make sure it has not been turned to "OFF". Make sure your filter access door and furnace door are secure. Many of the furnaces have a switch activated door for your safety. When the door is not completely on the furnace will not operation. This keeps the furnace from coming on when someone is servicing the blower or filter.
3. If your outdoor unit is running listen to determine if the fan is the only thing running or is the compressor running too?
4. Turn off your electrical power to the outdoor unit by pulling the disconnect switch or turn off the indoor circuit breaker. Take the screws off your air conditioner control access panel. Check with a multi-meter to make sure the power is actually off. Touch the top of the compressor. Is the compressor very hot? If the compressor is hot then the compressor could be out on thermal over-load. You need to wait and let the compressor cool down before you test your system again. Use water from a hose and gently let it run over the compressor to cool it down quickly. Sometimes it can take 2 or 3 hours for a compressor to cool down. After it has cooled down reapply power. Did the compressor start? Did the fan start? If the fan did not start with the compressor then this is why the compressor over heated. Check your fan motor and fan run capacitor to make sure the fan blade is free and the capacitor is in good shape. You can check the fan bearings by spinning the blade by hand the blade should continue to spin 3 to 5 seconds after you spin it. If it doesn't then you probably need a new fan motor. Another reason the compressor over heated could be that the system is low on refrigerant. Is the suction line (the line with the black insulation) cold like a cold coke can right out of the refrigerator after the unit runs for 10 to 15 minutes. If it is not cold, then you need to add some refrigerant. The refrigerant is what keeps the compressor running cool. If the system is low on refrigerant then you do not get the cool gas coming back to keep the compressor running cool. The compressor over heats and this will eventually melt the windings down in the compressor and contaminant the whole refrigeration system! This is not good. Eventually the compressor will ground out and you will need a new compressor or new system. Make sure that suction line is cold or you might be low on refrigerant charge. You will need to call a service technician to charge up your system if it is low. Now EPA requires that you be licensed and certified to purchase and use refrigerants.
5. Inspect your wiring to make sure that you do not have any burnt connections. Repair the burnt connections if you have some.
6. Inspect the capacitor/capacitors to see if they are swollen looking. If they are swollen purchase a new capacitor from our capacitor page.
7. Take the compressor terminal cover off and inspect the terminals on the compressor. Sometimes the compressor terminal cover can be a bear to take off. Use a screw driver to release the metal clip that holds the cover on. Sometimes the cover slides off. Sometimes the terminals unplug from the compressor. If any of the compressor terminals are burnt then you could probably use our Term-Lok compressor terminal repair kit to repair the terminals. See Term-Lok compressor terminal repair kit above on this page.
8. Inspect your contactor. Is your contactors points look burnt? You might need to purchase a contactor.
9. When you plug in the disconnect and apply power to your outdoor unit does the fan start and the compressor try to start, but make a "UGGGG" sound. This means the compressor is locked up. The compressor is an electric motor, enclosed in a case, with a piston similar to what you would find in a car. When you hear that "UGGG" sound it is telling you that the piston is locked up. You need to try to unlock the piston. If you can not unlock the piston then you need a new compressor or air conditioning system. You might want to purchase a Super-Boost hard start capacitor. The Super-Boost is also listed above on this page. If you purchase and hook-up the hard start capacitor and the compressor still will not start then you will need a new compressor or system. I say, "System" instead of just outdoor unit because it is recommended that you change both the outdoor unit and the indoor evaporator coil when you install a new system. Manufacturer says that it will damage the outdoor unit if you do not change the evaporator coil too.
 Compressor Terminal Repair Kit
Mainstream Engineering, Rockledge. Fla., a manufacturer of hvacr aftermarket service/maintenance products, introduces QwikLug, a compressor terminal repair kit for all compressor brands, sizes and configurations used in industrial, hvacr, appliance, electrical, military and testing/monitoring applications. Instead of Allen wrench setscrews, QwikLug is easily tightened onto spade-style compressor terminals with front-access Phillips head set screws.
Best of luck! I hope this has helped you to trouble-shoot and repair your air conditioner! I hope you can get your air conditioner up and running again soon! I admire you for trying to repair your air conditioner yourself. Please be careful and make sure the power is turned off and you do not get cut on those sharp sheet-metal edges. Just take your time and think things out step-by-step.
|
|
How Air Conditioners Work
Air conditioners employ the same operating principles and basic components as your home refrigerator. Refrigerators use energy (usually electricity) to transfer heat from the cool interior of the refrigerator to the relatively warm surroundings of your home; likewise, an air conditioner uses energy to transfer heat from the interior of your home to the relatively warm outside environment.
An air conditioner cools your home with a cold indoor coil called the evaporator. The condenser, a hot outdoor coil, releases the collected heat outside. The evaporator and condenser coils are serpentine tubing surrounded by aluminum fins. This tubing is usually made of copper.
A pump, called the compressor, moves a heat transfer fluid (or refrigerant) between the evaporator and the condenser. The pump forces the refrigerant through the circuit of tubing and fins in the coils.
The liquid refrigerant evaporates in the indoor evaporator coil, pulling heat out of indoor air and thereby cooling your home. The hot refrigerant gas is pumped outdoors into the condenser where it reverts back to a liquid, giving up its heat to the outside air flowing over the condenser's metal tubing and fins.
Throughout the second half of the 20th century, nearly all air conditioners used chlorofluorocarbons (CFCs) as their refrigerant, but because these chemicals are damaging to Earth's ozone layer, CFC production stopped in the United States in 1995. Nearly all air conditioning systems now employ halogenated chlorofluorocarbons (HCFCs) as a refrigerant, but these are also being gradually phased out, with most production and importing stopped by 2020 and all production and importing stopped by 2030.
Production and importing of today's main refrigerant for home air conditioners, HCFC-22 (also called R-22), will begin to be phased out in 2010 and will stop entirely by 2020. However, HCFC-22 is expected to be available for many years as it is recovered from old systems that are taken out of service. As these refrigerants are phased out, ozone-safe hydrofluorocarbons (HFCs) are expected to dominate the market, as well as alternative refrigerants such as ammonia.
Maintaining Your Air Conditioner
An air conditioner's filters, coils, and fins require regular maintenance for the unit to function effectively and efficiently throughout its years of service. Neglecting necessary maintenance ensures a steady decline in air conditioning performance while energy use steadily increases.
Air Conditioner Filters
The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace or clean its filters. Clogged, dirty filters block normal air flow and reduce a system's efficiency significantly. With normal air flow obstructed, air that bypasses the filter may carry dirt directly into the evaporator coil and impair the coil's heat-absorbing capacity. Keeping the filter clean can lower your air conditioner's energy consumption by 5%–15%.
For central air conditioners, filters are generally located somewhere along the return duct's length. Common filter locations are in walls, ceilings, furnaces, or in the air conditioner itself. Room air conditioners have a filter mounted in the grill that faces into the room.
Some types of filters are reusable; others must be replaced. They are available in a variety of types and efficiencies. Clean or replace your air conditioning system's filter or filters every month or two during the cooling season. Filters may need more frequent attention if the air conditioner is in constant use, is subjected to dusty conditions, or you have fur-bearing pets in the house.
Air Conditioner Coils
The air conditioner's evaporator coil and condenser coil collect dirt over their months and years of service. A clean filter prevents the evaporator coil from soiling quickly. In time, however, the evaporator coil will still collect dirt. This dirt reduces air flow and insulates the coil, reducing its ability to absorb heat. To avoid this problem, check your evaporator coil every year and clean it as necessary.
Outdoor condenser coils can also become very dirty if the outdoor environment is dusty or if there is foliage nearby. You can easily see the condenser coil and notice if dirt is collecting on its fins.
You should minimize dirt and debris near the condenser unit. Your dryer vents, falling leaves, and lawn mower are all potential sources of dirt and debris. Cleaning the area around the coil, removing any debris, and trimming foliage back at least 2 feet (0.6 meters) allow for adequate air flow around the condenser.
Coil Fins
The aluminum fins on evaporator and condenser coils are easily bent and can block air flow through the coil. Air conditioning wholesalers sell a tool called a "fin comb" that will comb these fins back into nearly original condition.
Condensate Drains
Occasionally pass a stiff wire through the unit's drain channels. Clogged drain channels prevent a unit from reducing humidity, and the resulting excess moisture may discolor walls or carpet.
Window Seals for Room Air Conditioners
At the start of each cooling season, inspect the seal between the air conditioner and the window frame to ensure it makes contact with the unit's metal case. Moisture can damage this seal, allowing cool air to escape from your house.
Preparing for Winter
In the winter, either cover your room air conditioner or remove and store it. Covering the outdoor unit of a central air conditioner will protect the unit from winter weather and debris.
|
|
|